An ecosystem consists of two types of components:

(a)   Abiotic components:

This includes the non-living components of the ecosystem. These are physical and chemical factors.

1.             Physical factors include: Sunlight, shade, wind, humidity, rain, types of soil and its pH.

2.           Chemical factors:

                  (i)            Inorganic substances:  includes C, H, O, N, P, S, and H2O etc involved in material cycle.

                  (ii)           Organic substances: includes carbohydrates, proteins, lipids etc present in biomass.

(b)   Biotic Components:

All the organisms are part of biotic components. They are grouped into three categories:

(1)   Produce (2) Consumers (3) Decomposers.

(1)   Producers:

All the green plants of an ecosystem are collectively known as producers. The green plant have chlorophyll by which they trap solar energy  and convert it into carbohydrate by using CO₂ and H₂O .this process is known as photosynthesis. So, green plants are called autotrophs (auto-self: troph-food) as they prepare their own food. No ecosystem can survive without green plants.

(2)   Consumers:

        They are known as heterotrophs (hetero- other, trophs-food) as they are directly or indirectly depend upon producers for their food. They are categorized as follows:

(i)           Primary Consumers or Herbivores:  they are first order consumers because they depend upon green plants or producers for their food eg. Cow, goat, rabbit, deer.

(ii)         Secondary Consumers: they are also known as primary carnivores because they depend upon primary consumers for their food.eg. Fox, cat, frog.

(iii)       Tertiary Consumers:  they are also known as secondary carnivores because they depend upon secondary consumers for their food eg. Owl, peacock wolves etc.

(iv)        Quaternary Consumers: they are top carnivores which depend upon tertiary consumes for their food and not eaten by any other animals eg lion, tiger, crocodile etc.

(3)   Decomposers:

They are small microscopic (fungi, bacteria) organisms and occur everywhere in ecosystem i.e. and, air and water. They decompose dead organic matter into simpler compounds. They are also known as saprophytes.

The producers form first trophic level of food chain, herbivores form the second trophic level and carnivores form third trophic level.